Tracking the reputations of sources from which electronic data originates is an important form of computer security. For example, the reputations of email addresses and domains can be tracked to identify trustworthy versus potentially malicious email senders and file signatures. The amount of reputation data to track is becoming increasingly broad as malicious users abandon single point sources such as open proxies, and move to dispersed distribution methods such as the use of botnets and compromised webmail credentials. Tracking the reputations of dispersed sources requires larger and broader reputation databases to remain effective. As the number of database records increases to track reputation by sender email address, sender domain and Internet Protocol (IP) address (IPv4 or IPv6), reputation tracking uses large amounts of storage. For example, a traffic shaping device storing only 50 bytes per Internet Protocol Version 4 (IPv4) address in a 32 bit process space can store reputation information for approximately 50 million IP addresses. This may sound like a lot, but it is well below the potential 4 billion IPv4 address space size. Even if a central data warehouse is used to track large amounts of reputation data, it is desirable to store reputation data on the client side as well, for retrieval performance and storage data gathering.
As explained above, it is desirable to track the reputations of large numbers of electronic content sources. Yet, conventional reputation tracking systems can often not practicability store the amount of data required to do so, even on the server side. Furthermore, it is simply not possible for conventional reputation tracking systems to store such large amounts of data on the client side. It would be desirable to address these issues.